Means for heat-treating material



Feb. 14, 1950 H. A. D REFFElN MEANS FOR HEAT-TREATING MATERIAL 4Sheets-$heet 1 Filed Sept. 25, 1947 ant ATTORNEYS Feb. 14, 1950 H. A,.DREFFEIN MEANS FOR HEAT-TREATING MATERIAL 4 Sheets-Sheet 2 Filed Sept. 251947 as B Q mm

mam R. W0

ATTORNEYS Feb. 14, 1950 H. A. DREFFEIN 4 2,497,442

MEANS FOR HEAT-TREATING MATERIAL Filed Sept. 25, 1947 4 Sheeis-Sheet sPRE H EA TIA/G CHAMBE COOL WATER HEATING CHAMBER H EATED WATER OUTVEN'I'OR.

ATTORNEYS Feb. 14, 1950 4 Sheets-Sheet 4 Filed Sept. 25, 1947 PREHEATINGCHAMBER HEATING CHAMBER.

ATTORNEYS Patented Feb. 14, 1950 UNITED STATES "PATENT OFFICE MEANS FORHEAT-TREATING MATERIAL Henry A. Drefiein', West Chicago, 111.Application September 25, 1947, Serial No. 776,090

4 Claims.

This invention relates to improvements in means for and methods ofheat-treating material such as metal and has for an object annealing,normalizing or malleableizing of metal in the form of strips, sheets, orthe like, and castings.

Heretofore, in the normalizing of cold rolled strip, for example, it hasbeen the practice in certain batch" methods to encase the coiled stripin a species of single or double walled retort and to apply heat eitherto the exterior of said retort or between the walls.. This is expensiveand requires considerable time. In another practice, electrical meanshas been utilized for direct heating, but this, too, is generally quiteexpensive. Also, endeavors have been made to utilize indirect heatingmeans by burning gas in appropriately arranged tubes to render themradiant. In this last process, the heat to which such tubes mustnecessarily be subjected to obtain the desired heating of the strip orsheets is sooner or later destructive of the tubes. In still anotherpractice, for example, as described in my Patent No. 2,233,474, datedMarch 4, 1941, the strip or sheet has been directly heated in a heatingzone by burning a rich fuel gas mixture therein after having beenindirectly heated in a preheating zone, where the partially burned gasesfrom the heating zone are burned in radiant tubes.

My presently disclosed process entirely eliminates the use of suchindirect heating in radiant tubes and thereby avoids combustion problemsinherent in burning fuel mixtures inside-tubes, avoids the expensiveperiodic replacement of such tubes, and at the same time avoids thedeleterious corrosive, effects on the strip itself which previously wereconsidered unfavorable in the burning of fuel gas in direct contact withthe metal being heated.

In my present process, I first preheat the cold rolled strip as it isfedthrough a preheating chamber, after being uncoiled and flattened. It isnext passed through a main heating chamber to which is suppliedpartially burned fuel gas abnormally rich in gas content'so as to createa reducing atmosphere to preclude oxidation or tarnishing of the strip,while at the same time,

heating zone by a stream ,of additional air and is,

further combustedtherein to directly; preheat the strip. The hot gasesfrom the preheater are passed in heat exchange with the stream ofadditional air entering the preheater zone to improve the overall heateiilciency of the process. 'Another portion of the partially burnedgases from the heating zone is diverted into the coolingv chamber tomaintain a controlled, non-oxidizing atmosphere therein.

Another object consists in the utilization of a generally similarprocess, except as to temperature ranges, to sheets or other metalarticles for annealing the same.

Another object is the provision of a novel burner arrangement for thepreheating chamber wherein air, preheated by exchange with thepreheating chamber combustion products, is utilized to aspirate orinduce partially burned fuel gases from the heating chamber into thepreheating chamber for additional combustion therein with the preheatedair.

Another object is the provision of a novel, uniformly-cooledstrip-supporting roller which will remain undistorted, even under widevariations of operating conditions, including prolonged work stoppagesduring which the top of the roller,

may be subjected to relatively greater heat than the bottom, causing itto warp. This improved cooling permits the use of ordinary steelrollersinstead of the relatively expensive alloy rollers conventionallyemployed for this purpose.

Another object in connection with the cooled.

illustrating one embodiment of my invention and. showing the preheatingchamber and the partsassociated therewith;

Fig. 1a is a similar section of a continuation of the portion shown inFig. 1, showing the main heating chamber and parts associated therewith;

Fig. lb is'a similar section of the remaining portion of the apparatusshowing the cooling chamber and the parts associated therewith;

Fig. 2 is an enlarged sectional view of one embodiment of theinternally-cooled roller forming part of the present invention;

,, Fig. 2a is a sectional view-of Fig. 2 taken alongihcline 2072a;v 1

Fig. 3 is a vertical transverse section of the preheating chamber takenalong the line 3-3 of Fig. 1;

Fig. 4 is a vertical transverse section of the heating chamber takenalong the line 44 of Fig. 1a;

Fig. 5 is a fragmentary enlarged view of either Figs. 1 or 1a showingone form of the aspirating or Venturi means employed for inducing richgases from the: heating chamber into. the preheating chamber;

Fig. 5a is a sectional view of Fig. 5 taken along, the line 5a--5a; and

Fig. 6 is a vertical transverse view ofthe heat exchanger portion of theapparatus shown in. Fig. 1 and is taken along the line 9-6;

My apparatus generally is; constructed in the: usual manner ofrefractory materials, properly reinforced and supported, suchdetailsformingno specific part of my invention other than as they enterinto the general combination.

In the illustration, at the charging' end; designated; by" numeral 2 isprovided a wall; 22 having an outlet opening 23 for material. such: as astrips 2 of steel being heat-treated, the opening 23 being CIOSQiblB' toany. extent desired: by a fire brick door 2'6 suspended by chain: 21;from the counter-weighted lever. 28; The strip or sheet 24 is adapted:to be fed continuously through the apparatus, there being a; series of;transverse, spaced, intermediate: rollers or: rolls 29, rotated at suchspeed as: to make. their peripheral, linear velocity-identical withithefeeding rate, so that-the metal of thestrip Willnot be marred? or."scratched; The rolls. 2'99 situated; at' hot locations in. theapparatus. will. be: cooled: internally in accordance with: a. portionof the: invention to be described subsequently herein. It'willbeunderstood" that the. cold rolled: strip, if originally supplied coiled,will be unrolled' and; flattened before delivery to the: apparatus... Atthe" discharge end 3'1 isprovided a pain of pinchv rolls; as they-aretermed; designated by. numeral; The-objectof the pinch rolls istto".makerthei smallest-possible furnace opening.torminimizeathe escapeof"furnaceagasesitherethrough. They also: assist in efiecting themovement. of: the: metal by; grippingit and drawing it' through. thefurnace. All of -the: rolls; for convenience; may be driven. by acommon: drive chain: 33 and sprockets 34;. one, of the latter beingprovided? for: each: of: the intemnediate andfeeding: rollers; as:illustrated: diagrammatically in Fig. 1b.;v for example: The? chain 33is. provided' with: a takeup. device, gene erally designated 36',includingra vertical. loop in; the chain andi a floating sprocket:supporting: weights 33. At: the rear end of the' chain: 33? a doublesprocket 3'4ulisprovided having one por-- tiorr for supporting thevchain: 33-: and another: portion for su-ppotring the drive chain 39; thelatter'being connected to one portion of another sprocket 41 the otherportion of: sprocket 41 driving a chain 412 which turns the lower; one:of. the pinch rolls 32. The sprocketrdzl: is rotatablydriven throughbeveled: gearing? 43 and shaft 44 by a combined: electrical: motor. and.speed re ducer'F; diagrammatically;illustrated in'Fig. 1b;

Ati the charging. end? of: the furnace-is provided whatil? t'erma;preheating chambenA; Extending from the: rear." end: of: that? is: themain heating. chamber 3; there being a: bridgeewa'll or: partition 46:between the. chambers;. At the opposite end of the main: heatingachamber-is a cooling chamber". C;whichmay-comprisezas single chambersuch as illustrated in Fig. 1b, or where desired;

it may comprise a number of successively disposed cooling cells, forexample as disclosed in my previous Patent No. 2,233,414, abovementioned.

Along the sides of the main heating chamber B are provided a series ofburners generally designated 41, which as shown in Fig. 4, are connectedto gas and air supply lines 48 and 49 controlled by valves 48a and 49a,respectively. Each burner is disposed; to discharge into a ceramicthroat member 51 and is' set back therefrom suitably to permit theentrance of secondary air.

A combined Venturi or aspirating means and secondary burner: means,generally designated 52., is providedto transfer to the preheating zoneand complete the combustion of a portion of the rich, partially burnedgases which will exist in the heating zone. This means is best shown inFig; 5 and comprises a pressure regain tube 53 set in the separatingwall 46 and a jet member 54 also: having: a low :pressurearea 56therebetween; which. is: defined: by thespacing. between; the"vseparating; wall 4d the" upright outside: Wall; 5:71 ofz the: heatingchamber. Bi. Qne; or: more.

1 sets of aspiratin'g: elements 53541 may be. pro:--

vid'ech. depending: orctheir.= size; and on. the:combustionrequirementsi in. the preheating chamber A. Eachof the-jetmembers-25:4 is; sealed tightly in: the: wallv 5:!towpreventtheinduction of second? ary air' frzonrthe outside? in; what.has. previously been. the: conventional manner, thereby provide ing.that. the secondary air required: to complete: burning of thezri'chgasesrtransierredfrom cham.-- ber B- to: chamber:A willber supplied:only by. the; jet members: 541. As best. shown; in: Fig.1 3,v the.means-52;,illustrated, emp1oysl3 setsof. the above mentionediaspiratingielements 53-54. Eachof. the: jet: members: Ed? is. providedwith:aplurality" (in; this case: 6) of: circularly" arranged. dischargeiopenings 513.; communicating through. conduit 59 and. control: valve 6 lwith. the. manifold: 62' which. is; supplied. with: air: through the;main: supply line:63; Eachof. the jet members. 5.4 is:likewiseaprovided. with: as. centraldischarge opening 64;

. Whichi'sz comlnunicatiom throughr. conduit Gfii and"; control valve 61with thezair supply'manifoldi 62;. it; will. be seen. that. the. airsupplied. through discharge: opening-4'14 is controllable independentlyof air supplied? through. the other dischargeopening. 58... Thisarrangement.permits at very fine; Vernier-like. adjustment andClosecontrol of. therair' needed. for" aasustaining com-- 'bustion: in;the?v preheating. chamber: A.. The main: valve; 61;. controlling the".discharge through: the six:openings 58 of each. jetlmernber; maybe: adI-justed to: provide: theapproximate: amount of: air required. and the:valve 61 controlling. the air' through opening 64 may be adjustedto'supply the exact. amount. of air required.

The rich; partially burned gaswhichtis drawn from theheating-chamber-B-into the low pressure: space- 56- will be at ahigher temperature: thanthe minimum. required. for it's ignition. and, consequently, uponmixingwith; the air' issuing: fromzthejets 5L4; it; will be instantly'ignitedt and; its' combustioncompleted. in the. preheating chamher A'.

In: addition this arrangement; provides; a convenientzaway ofincreasingthezinduction.from. the.

heating; chamber? without; increasing the air: sup-- ply," through".pipe: 63-; By shutting off" the center"- opening." 64; or: by throttlingit in a suitable;

5.83 increases the velocity of' 'the air pass-- gher pressure: through.the. remaining openings-- chamber byv lowering the pressure at 56.

5. ing into the throat member 53 thereby increasing the amount of gasinduced from the heating This assists gas in leaving the furnace yetavoids the objectionable high iurnacepressures that otherwise would'haveto be employed for this purpose.

The top of the preheating chamber A, forwardly of the tube 53, isenlarged to provide a secondary combustion zone 68 therein. At theforward end of the preheating chamber A, as best shown in Fig. 1, is inthis instance provided an outlet port 69 connected by a flue or duct Hinto a heat exchanger 12. The conduit 22 is illustrative of only one ofmany means, which will occur to one skilled in the art, of conveying theburned gases from-the preheating chamber A to the preheater 12. Inanother means (not shown) which may be preferred in some instances thehot gasses will be drawn out of the forward opening 23 beneath the door26 and thence conveyed to the preheater 12. The latter is provided'witha series of air tubes 13 and gases burned in the preheating chamber aredrawn upwardly through the preheater 12, around the tubes 13, and intothe duct 14 which is connected into an exhaust stack or chimney (notshown).

As best shown in Fig. 6, the tubes 13 are in communication at theirinlet ends 16 to receive air from a blower M and at their opposite endsare in communication with a heated-air collecting chamber 11 into whichis connected the preheated air supply line 63 already mentioned andwhich supplies air to the aspirating means 52. The blower M is motordriven and, as shown diagrammatically in Fig. 6, provides the motivepower for moving the air through line 63. Thus, for maximum heatefficiency of the apparatus the amount of heat in the preheater exhaustgases, in excess of the maximum required to move them efficiently up theexhaust stack, will be extracted for use in preheating air in line 63.

A cooler 18 is mounted atop the cooling chamber C and has an inlet 19and an outlet 8| com- .municating, respectively, with forward andrearward zones of the cooling chamber. A blower, generally designated82, is provided in the cooler outlet 8| and is effective to draw gasesof the cooling chamber atmosphere into the inlet 19, .cool them, and ifdesired, dehumidify and desulphurize them, and direct them back into thecooling chamber through. the outlet 8!. Thus, it will be seen that theflow of cooled gasin the cooling chamber C is ccuntercurrent to the flowof the strip 24 which will facilitate a gradual I temperature reductionof the strip as it proceeds through this chamber. While only one outlet9| is shown connected into the cooling chamber C, it will be preferredin some instances to provide a number of these outlets spaced atintervals along the cooling chamber to speed up the rate of cooling,where an increased rate of cooling is desired over that obtainable withthe single outlet shown.

Another important part of the present invention resides in theinternally cooled roll which -I have provided for use with thisapparatus and which is best shown in Figs. 2 and 4. In this instance,the roll is made up of a cylindrical or tubular section 83 joined as bywelding at 84 to the journal members 86 and 81 at the ends there- 34 andis .further provided with abore or axial passage 93 within'which isinserted a stationary spray tube 94 connected by piping 99 to a coolingwater inlet. The portion of the pipe 94 within the journal member 81constitutes the cooling water inlet and the annular space 95 between thebore 93 and the tube 94 constitutes the cooling water outlet. .'Thisoutlet is restricted, by making it with a cross-section as small as canbe employed and still carry away all the water needed, in order that thelevel of water in the roll be maintained as high as possible for themaximum cooling effect. the water level, additional outlet-restrictingmeans in the form of the baflie I00 is provided. This bafile, beingattached to the outer tube portion 83 as by welding at lllla, isprovided with an opening lfllb to receive the spray tube, and has anumber of peripheral openings llllc to permit the restricted outletflow; of the cooling water. A valve 91, diagrammatically shown in Fig.4, controls the amount of cooling water admitted to the inside of theroll. An individual valve 91 may be provided for each roll or one valvemay control the cooling water in a number of rolls, depending on therequirements of a particular installation. A stationary funnel orcooling member 98 is disclosed below the outlet end member 81 to collectthe heated water discharged from the roll and divert it to the outletpipe 99.

An important feature of the roll cooling means disclosed resides in theupwardly disposed spray openings I0! which are formed along the lengthof the spray tube 94. Conventional internally cooled rolls have not beenprovided with upwardly directedsprays of this nature but instead havemerely passed water through, usually in one end and out the other and aslong as the roll was rotating, it remained cooled in a more or lessuniform manner. However, as soon as the roll stopped, there was always aspace at the top, either due to air collected in that position or due tovapor formed at the top, which caused the upper portion of the roll toheat at a much greater rate than the bottom portion in contact with thewater. This uneven heating caused buckling beyond the proportional limitof the material in the roll and thenceforth, the roll would wobble in aneccentric manner causing the strip to take on a series of waves as itwas moved from one roll to the next. The cooling means illustrated inFig. 2 obviates this difliculty for, even when the roll is stopped forlong pe-'- riods of time, the upper portion remains just as cool as thelower portion due to the upwardly directed sprays through openings llll.A still further refinement of this invention is illustrated in Fig. 2awhere it will be seen that the openings l9l are disposed, not onlyupward as previously explained, but upward in a tangential, non-radialmanner. With this arrangement, the water sprays approaching the wall ofthe tubular member 83 in amore or less tangential manner cause the watertherein to swirl in one direction '(clockwise in Fig. 2a) around theinside of the roll thereby increasing the heat transfer and minimizingthe volume of cooling water required.

Another important feature of the present inventlon, which greatlyreduces heat loss from the apparatus to the cold rolls, is shown in Fig.2a which illustrates a shielding member I92 made of ceramic or otherheat insulating or heat re fleeting material and formed with aroll-receiving trough I09 The shielding member surrounds, in spacedrelation, asubstantial part of Furthermore, to maintain I r ea-44s i theroll, all except the 1 I per portion which supports the strip 26. Itminimizes heat transfer from the apparatus to the rolls :by bothconduction and radiation, especially the latter. In one particularinstallation, .for example, use of a ceramic shield of the kindillustrated has reduced the heat loss to each roll by more than one-halfwithout in anyway impairing the stripsupporting runctionoi the rolls;

'1 have found that the heat loss from the loottom half or the roll is,for :all practical purposes, insignificant and from this "I estimatethat the heat loss to the roller taken as a whole is less than half theheat loss to conventional wateroooled rollers which are not so shielded.

By the use of my internally cooled roll, together with the heat !s'hielddescribed, I can dispense completely with the expensive alloy rollspreviously considered essential for high temperature processes of thisnature and can use rollers or ordinary steel throughout. It will begenferallydesirab'le to use the internally cooledrollers in both theheating and cooling chambers as well as for the elevated temperatureportions of the preheating chamber. The entering rolls in the preheatingchamber, however, may be made of alloy steel without the internalcooling feature, since the strip will be up to heat at this location andthere is no problem of oxid accumulation on the rolls which wouldscratch the strip.

In normalizing, for example, cold rolled strip in the apparatusdescribed above, fuel gas in admixture with .air under pressure isdelivered to the burners 4! in the main heating chamber B and ignitedand the relative proportions of air and gas are :50 adjusted that onlypartial combustion of the fuel gas results. .I desire to maintain :anabnormally rich, reducing mixture of partially burned gases in the mainheating chamher to prevent oxidation of the strip or other metal passingtherethrough. .I contemplate maintaining a rich gas mixture in whichanywhere from to 50% excess gas is used.

In order to utilise this unburned fuel gas, I deliver air through thejet members 54 of the :aspi-rating means 52 which is effective to inducea portion of the rich gas in the heating chamber into the low pressurechamber 55 and thence into the preheating chamber .A for additional oom-=bustion. Proper regulation of the valves ti and -61 is made 'so as tocontrol the heating efiect in the preheating chamber. Some of the richgas will pass through the strip opening in separating wail-1'46 and thiswill be taken into account in adjusting the valves and -67 to pro- Widesufiicien-t air to substantially completely bur-n it. While it is mydesire to burn the gas in the preheating chamber as completely aspossible, .1 meter that the atmosphere therein be maintained slightly onthe reduo'mg side so as to prevent the oxidation 'of the stripespecially the portion thereoi near the rear or hottest end.

As the strip moves out or the chamber B into :and through the chamber'0, it .iscooled by gases circulated through "the cooler 18 and theblower $2. I contemplate, where it seems desirable, to operate thecooler at a low enough temperature to substantially dehydrate the gases;and furthermore, where it seems desirable, I contemplate washing thegases in a-scrubber associated with the cooler, or otherwise suitablytreating them, to desulphurize them-.-

The strip passing into the cooling chambe will be at .sufiioicnt-ly hightemperature to oxisiiz's' readily the presence or air. :Consequently,

I contemplate maintaining the cooling climber C at a pressuresufiicirrtly lower than the heat-'- ing chamber .13 to cause a portionof the Irish heating chamber gases to vilow'through theopening 12 5. Thegases in the cooling chamber eventually will b dissipated out of the endportion 31 but such loss will be constantly made up by inflow throughthe opening 2 5.

Thus, it will be seen that the partially burned gas in chamber B isdiverted in two directions: (a) the major portion is aspirated into thepreheating chamber .for a more complete burning; and (b') the remainderis caused to flow into the cooling chamber to maintain aspecialatmosphere therein.

in one method of normalizing strip with my apparatus, for example, Iregulate the supply of fuel gases and the speed with which such strip isfed through the apparatus so it attains a tern perature or between 1300F. when it reaches the br idg'e wall-4 B. After movement into the mainheating chamber B, this temperature is quickly raised to around 1700 F.preferably l650 F. to 1'80036. and with the water-cooled, shielded rollsI have disclosed may be operated at any desired temperature even as highas 2200" F.) and remains at about that point during the remainder of thetravel through the chamber B, which therefore functions not only tobring the metal to the desired maximum temperature but as a soakingchamber in which such temperature is maintained until the proper actionis had upon the metal. During the passage of the strip through thecooling chamber C cooling at first is relatively slow until the stripprogresses to a point where it is directly in line with the cold airemitting from the blower outlet pipe 8!. From then on, the temperaturedrop is more rapid and -the strip 'is preferably brought to 800 F. 'orless at the" point of discharge from the cooling chamber. This I term-for convenience a non-oxidizing temperature because such a strip is notsusceptible to quick oxidation or tarnishing under normal conditionsafter that temperature is reached.

'1 can also utilize this apparatus for annealing strip or metal sheets,in which operation the metal is brought to a temperature of around 800in passing through the chamber A, quickly raised to 1350" F. afterentrance into the chamber B, and is maintained at that temperatureduring the balance of their travel through E. Similarly to thenormalizing procedure described, the strip is lowered to a temperatureof 200 F. or less during passage through the cooling chamber C.

In the apparatus described, I am able eiiiciently and economically toobtain the desired heat treatment of the strip or other metal by directapplication of fuel gas mixture in a continuous operation and in such amanner as to substantially obviate the formation of scale or oxide onthe metal, and at the same time, contribute to the economy of operationby salvaging the unburned fuel for direct preheating use and for themaintenance of a reducing atmosphere in the cooling chamber.

It will be apparent that the specific method and apparatus describedherelnabove .is susceptible of variation and modification, and I do notwish to be restricted to such disclosure except as the claims, properlyinterpreted in view of the prior art, must be so limited.

I claim:

:1. Apparatus for thermally treating material comprising a structurehaving means to support move such material through a series of chambersincluding preheating, heating, and

cooling chambers, saidheating chamber having; g means to generate andsupply partially burned;

fuel gases thereto, means for conducting a per- 5 tion of the partiallyburned fuel gases from the heating chamber to the preheating chamber andburning the gases to amore complete degree for directly preheating thematerial in the preheating chamber, and means for conducting a portionof the partially burned fuel gases from the heating chamber to thecooling chamber to maintain a special atmosphere about said material in'therein, burner means, associated with said preheating chamber adaptedto directly preheat the material therewithin, means for conducting aportion of the partially burned gases from the heating chamber to saidburner means and 'means for supplyingan additional fuel component to thegases passing through said burner means for burning said gases to a morecomplete degree in the preheating chamber to directly preheat thematerial therewith, heat transfer means associated with a gas dischargeoutlet of said preheating chamber for transferring heat from the gasesburned therewithin to the supply of said additional fuel componentbefore it enters said burner means,-means for conducting a portion ofthe partially burned gases from the heating chamber to the coolingchamber and means associated with the cooling chamber for subjecting thelast-mentioned portion of gases to a special treatmentto provide aspecial atmosphere for the material in the cooling chamber.

3. Apparatus for thermally treating material comprising a structurehaving means to support and move such material through preheatingg andheating chambers, said heating chamber having means for generating andsupplying rich partially burned fuel gas mixture thereto, and Venturimeans for transferring a portion of said rich mixture to the preheatingchamber and mixing it with an additional fuel component to burn saidportion to a more complete degree, said Venturi means comprising apressure regain tube and a,

jet member spaced therefrom by a low pressure space and positioned todischarge into said tube, said low pressure space being inZcommunication with said heating chamber, said tube being incommunication with said preheating chamber, and means for placing saidjet in' communication with a source of said additional fuel component.

4. Apparatus for thermally treating material comprising a structurehaving means to support and move such material through preheating andheating chambers, said heating? chamber having means for generating andsupplying a rich partially burned fuel gas mixture thereto, and meansfor aspirating a portion of the said rich mixture to the preheatingchamber and mixing it with an additional fuel component to burn theaspirated portion more completely, said aspirating means comprising apressure regain tube and a jet member spaced therefrom by a low pressurespace and positioned to discharge into said tube, said low pressurespace beingfin communication with said heating chamber, said tube beingin communication with said preheating chamber, said jet member having aplurality of discharge openings each disposed to discharge into saidtube, conduit means for placing each of said discharge openings incommunication with a source of said additional fuel component, and meansfor controlling the flow of said component through at least one of saiddischarge, openings independently of the flow through the rest.

HENRY A. DREFFEIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

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